Flexible polyurethane foam (PUFF) is a versatile product. Though the PUFF has excellent properties, they lack flame retardance. To make the material more useful, the incorporation of flame retardant (FR) is inevitable. To impart these specific characteristics, Sepia officinalis bone powder (SOBP) and aluminium hydroxide (Al(OH)3) combined together are used as a filler (SBPA) along with PUFF in this current investigation. SOBP is used by varying different percentages (1 % to 5 %) (1 %-SBP1, 2 %-SBP2, 3 %-SBP3, 4 %-SBP4, and 5 %-SBP5). Based on the UL 94 Horizontal Burning (HB) rating test, the best rating was observed with 3 %-SBP3. Al(OH)3 was loaded by varying from 1 % to 5 % (1 %-SBP3A1, 2 %-SBP3A2, 3 %-SBP3A3, 4 %-SBP3A4, and 5 %-SBP3A5). UL 94 HB results with a burning rate of 1.3 mm/s for the SBP3A4 which is lesser than neat PUFF (PUFNF). Tensile strength (TS) was observed higher for SBP3A3 sample with 0.257 MPa (172 % elongation at break). Density and RR values were observed in the range of 34–46.5 Kg/m3 and 30–34, respectively. XRD analysis reveals SOBP fillers with a particle size of 0.24 µm and the crystallinity index values depict the amorphous nature. The second stage degradation temperature was found to be increased to 363 °C from 303 °C for both SBP3 and SBP3A4 filler addition in TGA analysis. SEM analysis decoded the open cell (OC) structure further confirms the formation of PUFF. The present study confirms the improvement of UL 94 HB rating and other properties in the prepared PUFF.